SERUM ANTIBODIES AGAINST PHOSPHOLIPASE A2 RECEPTOR – REFERENCE RANGES AND DIAGNOSTIC VALUE IN BULGARIAN PATIENTS WITH PRIMARY MEMBRANOUS NEPHROPATY
Keywords:
primary membranous nephropathy, anti-phospholipase A2 receptor antibodies, reference rangesAbstract
The development of nephrotic syndrome in the disease membranous nephropathy is most often observed in adults. Literature data indicate that its pathogenesis is multifaceted. In a larger percentage of cases, they are defined as primary membranous nephropathy, which currently has an unclear etiology. It has been established that in the pathogenesis of primary membranous nephropathy, the main role is played by autoantibodies produced by the body against the phospholipase A2 receptor (anti-PLA2R1), which are expressed by human renal podocytes. Other antigens, such as thrombospondin type 1 domain-containing protein 7A and neural epidermal growth factor-like-1 protein, have also been associated with this disease, especially in cases with negative autoantibodies directed against the phospholipase A2 receptor. In recent years, a large number of new antigens associated with this disease have been discovered. However, in 10%-15% of cases, membranous nephropathy antigens remain unknown, and their pathogenesis remains unclear. Currently, interest in clinical laboratory practice directed at these antibodies is attracting increasing attention in terms of diagnosis and monitoring of the disease. Our study was conducted among a group of Bulgarian patients diagnosed with membranous nephropathy, which was proven with the help of a kidney biopsy. The goal we set was to determine the reference ranges for autoantibodies directed against the phospholipase A2 receptor among the Bulgarian population, as well as to determine the diagnostic and prognostic value of these antibodies. The study design included the study of a total of 233 individuals, of whom 120 were clinically healthy individuals and a group of 113 patients. The patient group included three groups - primary membranous (n =52), secondary membranous (n =12) and other (n = 49) nephropathies. The concentration of serum autoantibodies was determined using a kit for quantitative determination of serum antibodies against phospholipase A2 receptor from EUROIMMUN. The obtained values were read using a microplate reader. We obtained processed the determination reference ranges for the indicator antibodies against the phospholipase A2 receptor. A cutoff value of 19.84 RU/ml was also determined, which allows the diagnosis of primary membranous nephropathy, as well as the differentiation of these patients from other forms of membranous nephropathy. Therefore, our data confirm the usefulness of determining the serum concentration of these autoantibodies in the diagnosis. Their good correlation with the clinical condition of patients indicates the possibility of using them in clinical practice to monitor disease activity, select the right treatment, and predict the prognosis of the disease. The aim of analyzing the severity of the impact of autoantibodies directed against the phospholipase A2 receptor on clinical effectiveness is to improve the quality of life of these patients
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